13 Therefore, prepare your minds for action; be self-controlled; set your hope fully on the grace to be given you when Jesus Christ is revealed. 14 As obedient children, do not conform to the evil desires you had when you lived in ignorance. 15 But just as he who called you is holy, so be holy in all you do; 16 for it is written: "Be holy, because I am holy." 17Since you call on a Father who judges each man's work impartially, live your lives as strangers here in reverent fear. 18 For you know that it was not with perishable things such as silver or gold that you were redeemed from the empty way of life handed down to you from your forefathers, 19 but with the precious blood of Christ, a lamb without blemish or defect. 20 He was chosen before the creation of the world, but was revealed in these last times for your sake. 21 Through him you believe in God, who raised him from the dead and glorified him, and so your faith and hope are in God. 22 Now that you have purified yourselves by obeying the truth so that you have sincere love for your brothers, love one another deeply, from the heart. 23 For you have been born again, not of perishable seed, but of imperishable, through the living and enduring word of God. 24 For, "All men are like grass, and all their glory is like the flowers of the field; the grass withers and the flowers fall, 25 but the word of the Lord stands for ever." And this is the word that was preached to you.

How do we ‘be holy’ and why should we want to?

Ephesians 5:1-5

1 Be imitators of God, therefore, as dearly loved children 2 and live a life of love, just as Christ loved us and gave himself up for us as a fragrant offering and sacrifice to God. 3 But among you there must not be even a hint of sexual immorality, or of any kind of impurity, or of greed, because these are improper for God's holy people. 4 Nor should there be obscenity, foolish talk or coarse joking, which are out of place, but rather thanksgiving. 5 For of this you can be sure: No immoral, impure or greedy person - such a man is an idolater - has any inheritance in the kingdom of Christ and of God.

Now these things are obvious. We feel bad when we do them, maybe battleground is in the ‘grey’ areas. Trouble is Ephesians says there should not even be a hint of sin.

How can we be so holy?

Romans 5:1-6

1 Therefore, since we have been justified through faith, we have peace with God through our Lord Jesus Christ, 2 through whom we have gained access by faith into this grace in which we now stand. And we rejoice in the hope of the glory of God.

Truth is, we cannot be holy, we are holy, because God being holy accepts us through faith in Jesus. But it goes on

3 Not only so, but we also rejoice in our sufferings, because we know that suffering produces perseverance; 4 perseverance, character; and character, hope. 5 And hope does not disappoint us, because God has poured out his love into our hearts by the Holy Spirit, whom he has given us. 6 You see, at just the right time, when we were still powerless, Christ died for the ungodly.

So we do not become holy through suffering, but suffering is inevitable as salvation works in our life, just as inevitable as the struggle with sinful desires.

Romans 7:17-21

17 As it is, it is no longer I myself who do it, but it is sin living in me. 18 I know that nothing good lives in me, that is, in my sinful nature. For I have the desire to do what is good, but I cannot carry it out. 19 For what I do is not the good I want to do; no, the evil I do not want to do - this I keep on doing. 20 Now if I do what I do not want to do, it is no longer I who do it, but it is sin living in me that does it. 21 So I find this law at work: When I want to do good, evil is right there with me.

Naturally enough, faced with what can at times look like an impossible situation, we can be tempted to feel that it’s all too much. But here we can take heart in one of the key passages for Christians engaged in living a life which can so often fell like a battle.

Romans 8:1-4

1 Therefore, there is now no condemnation for those who are in Christ Jesus, 2 because through Christ Jesus the law of the Spirit of life set me free from the law of sin and death. 3 For what the law was powerless to do in that it was weakened by the sinful nature, God did by sending his own Son in the likeness of sinful man to be a sin offering. And so he condemned sin in sinful man, 4 in order that the righteous requirements of the law might be fully met in us, who do not live according to the sinful nature but according to the Spirit.

So we can dismiss condemnation, but how do we do that?

Hebrews 12:1-3

1 Therefore, since we are surrounded by such a great cloud of witnesses, let us throw off everything that hinders and the sin that so easily entangles, and let us run with perseverance the race marked out for us. 2 Let us fix our eyes on Jesus, the author and perfecter of our faith, who for the joy set before him endured the cross, scorning its shame, and sat down at the right hand of the throne of God. 3 Consider him who endured such opposition from sinful men, so that you will not grow weary and lose heart.

It’s all about Jesus.

It's worth saying a little at this point about condemnation (which can be rejected out of hand) and conviction (which is best embraced and acted on with urgency). It's easy to confuse the two, they can seem so similar. The thing to remember is that condemnation makes you feel unworthy and turns you away from God's help in shame. It makes you feel that you are beyond help and maybe that God is angry or dismissive of you. The conviction of the Holy Spirit however may make you feel bad, but it turns you toward God's help and makes you desire His presence and be reconciled to Him. I suggest you apply these tests when you next feel shame about something so you can tell whether it is the Holy Spirit or merely a temptation from the Devil.